Character printing apparatus



July 21,1970 I GHAAS 3,521,293

CHARACTER PRINTING APPARATUS Filed Aug. 7, 1964 5 Sheets-Sheet l INVENTOR.

J y 1, 1970 GHAA'S I 3,52 3% CHARACTER PRINT ING APPARATUS Filed Aug. 7, 1964 5 Sheets-Sheet 2 a I 9 I 6 I I 70' v I h M I 2 V, I

July 21, 1970 V G. HMS 3,521,293

CHARACTER PRINTING APPARATUS Filed Aug. '7, 1964 5 Sheets-Sheet {a T 1I2I I4|5|wm IIEBBBEII 8 O 47 IIEBIIHE 7 manna 6 FIG.4

July 21, 1970' G. HAAS CHARACTER PRINTING APPARATUS 5 Sheets-Sheet 4 Filed Aug. 7. 1964 July 21, 1970 G. HMS 3,521,293

CHARACTER PRINTING APPARATUS Filed Aug. 7, 1964 5 Sheets-Sheet 5 9 I 1 I I l 10 I I I I a I I 750 I I I I/ 1 United States Patent 01 fice 3,521,293 Patented July 21, 1970 Int. Cl. G01d 15/06; H041 15/34 U.S. Cl. 346-74 11 Claims ABSTRACT OF THE DISCLOSURE Character printing apparatus of the type where the impressions caused by several moving electrodes form a character. Delay elements progressively increasing from the electrode forming the bottom to the electrode forming the top of the character are selectively introduced to change the type character into italicized letters.

The invention relates to an electronically controlled character printing apparatus comprising recording members cooperating with a printing surface and adapted to produce thereon, under the control of electrical pulses originating from a character generator matrix, printed areas selected from a matrix of possible areas, said selected printed areas representing the desired character.

In printing apparatus of the above kind the character generator matrix generally consists of a magnetic core matrix provided with read-in wires or character set windings, each following the physical pattern of a different one of the characters or symbols which may have to be printed. The recording members may consist of mechanical printing members, such as a group of electro magnetically operable wires. Electrographic or ferrographic printing, that is the printing of an electric or a magnetic charge pattern corresponding to the desired character may be obtained by means of a plurality of energizable wires arranged transversely to the printing surface or one or more elongated energizable members extending parallel to said surface and cooperating with a movable conductive or magnetic member on the other side of said printing surface.

In many cases, especially in the printing of computer output data, it is desirable to have a certain group or category of data printed in a form which is visually distinct from the form or type in which the other data are printed. Such a visual distinction may for instance be obtained by utilizing italicized characters as against the normal perpendicular characters. In known mechanical high speed printers such a change in type of the printed characters is normally only possible by changing-over to a different series of types. This, however, due to involving movement of inertial masses, is relatively time-consuming and consequently is an impediment towards obtaining high printing speeds.

The invention has for its object to provide for an electronically controlled character printing apparatus of the above specified kind, in which the form or type of the characters printed may be almost instantaneously changed-over from one type to another, for instance in the time-interval between the printing of two consecutive characters, without thereby having to increase that interval over its normal length. Accordingly, in a particular embodiment the printing of normal perpendicular characters may alternate with the printing of italicized characters without impairing the printing speed.

According to the invention this object is achieved by the provision of at least one pulse delaying device in a pulse transmission path between the character generator matrix and the recording members, the pulse delaying device effecting a delay in the printing of a part of the selected areas.

In a preferred embodiment of the invention there is provided a plurality of pulse delaying devices, each exhibiting a different delay time and each adapted to delay the electrical pulses originating from the elements of a diiferent row or column of said character generator matrix.

The invention will be described more fully with reference to the drawing. In the drawing:

FIG. 1 illustrates the principle of an electrographic printer according to the invention comprising 9 fixed elongated printing-electrodes,

FIG. 2 serves to demonstrate the required delay-times of the energizing pulses to the various printing electrodes for obtaining italicized characters,

FIG. 3 schematically illustrates an embodiment of the invention,

FIG. 4 illustrates a further embodiment utilizing shiftregisters as pulse-delaying devices,

FIG. 5 is a pulse-time diagram relating to the embodiment of FIG. 4,

FIG. 6 is used to demonstrate the various delay-times in priting normal perpendicular (90) or italicized characters and FIG. 7 illustrates means for obtaining clock-pulses for the shift registers in the embodiment of FIG. 4.

The electrographic character printing apparatus shown in FIG. 1 comprises as recording members for printing an electric charge pattern upon a printing surface 11, nine parallel extending fixed line-electrodes 1-9 arranged on one side of the printing surface 11 and one movable line-electrode 10 on the other side of said surface. The printing surface 11, 'which may be a paper tape or a sheet recording paper, is adapted to be moved in the direction p, transverse to the direction of the lines to be printed, whereas the movable electrode 10 is adapted to be moved in the direction of the line to be printed, that is the longitudinal direction of the electrodes 1 9 at a constant speed V. Printing is done by applying electrical pulses to the various electrodes 1 9 with respect to the movable electrode 10 taking in account the momentary position of the latter. Such a pulse results in the establishment of an electric charge on the printing surface 11 at the location of the shortest distance between the relevant fixed electrode and the movable electrode at the moment of the arrival of the pulse on said fixed electrode.

By employing seven series of pulses each series selectively energizing a particular combination of fixed electrodes 1 9 any charge pattern representing a character or symbol corresponding to any selection out of a 7 x 9 matrix of dots may be printed. After having been printed the charge pattern is developed (made visible) in one of the well-known ways utilized in electrography, for example the xerography process.

The electric pulses applied to the electrodes 1 9 for generating a specific character are obtained by means of a character generator matrix 12 having nine horizontal rows, each connected to a different one of said electrodes. The character generator matrix 12 comprises in this case seven vertical columns, this matrix accordingly being a 7 x 9 array, to which the matrix of possible character printing areas corresponds.

The series of electrical pulses applied to the electrodes 1 9 for printing a desired character are obtained by energizing those elements in the character generator matrix 12 arranged in the physical pattern of said character and thereafter sequentially pulsing the vertical rows of the matrix 12 in synchronism with the displacement of the movable electrode 11. The pulsing of a vertical column of the character generator matrix 12 means that the pulses representing the intersections of the character to be printed with a vertical line are generated simultaneously. The sequential pulsing of the vertical columns means that the pulses representing the intersection of the character to be printed with a horizontal line, i.e. any of the fixed electrodes 1 9, are generated sequentially.

Due to the angle between the longitudinal direction of the electrodes 1 9 and that of the movable electrode 10 being always the same, the type of the printed character tends to be fixed. It would be possible to effect a change in the said angle by mechanical means, but this would not only complicate the apparatus, but also have its effect on the printing speed.

According to the invention the effect of a change in angle and thereby in inclination of the printed character is obtained solely by electrical means, to wit by inserting appropriate pulse delaying means 1 9 respectively between the character generator matrix 12 and each of the fixed electrodes 1 9.

By providing switching means with which these pulsedelaying devices may be switched in or out of circuit at will, the type of the character printed by the electrodes 1 9 in combination with the electrode 10 may be changed. Where the pulse-delaying devices 1 9' in that order exhibit a steadily increasing delay are simultaneously connected in series with their corresponding electrodes, a change in printed character from normal perpendicular type to italics will occur. The reverse occurs when all these delay devices are simultaneously short-circuited. If a movable electrode 10 extends at right angles to the longitudinal direction of the fixed electrodes 1 9 and it is desired that the characters be inclined with respect to the vertical by an angle a (FIG. 2), then the pulses supplied to the electrode 9 would have to be delayed by the time T9 which it takes for the electrode 10 to travel over the distance a. Accordingly when the distance between the electrodes is h It will be clear that the delay-time for the pulses applied to the other fixed electrodes should be correspondingly shorter, in general: for electrode k the delay time should be In FIG. 3 an embodiment of the invention is illustrated. The data to be printed arrive in coded form,'for

instance in binary form, from a computer, and are decoded in a decoding matrix 13. the decoding matrix 13 selects in the character generator matrix 12 the read-in wire following the pattern of the character or symbol represented by the information received by the decoding matrix 13. Each of the nine horizontal rows in the character generator matrix 12 may be connected, either directly or over a pulse-delaying device 32 39, depending on the position of the associated switches 22 29 to its corresponding recording electrode 1 9. The delaying times of the devices 32 39 are chosen in accordance with the above expression for 'r In the lower position of the switches 22 29 the characters are printed in normal perpendicular position. In the upper position of the switches the printed characters are italicized. The simultaneous actuation of these switches 22- 29 may be triggered by means of a special input signal to the decoding matrix 13, resulting in appropriate voltages being sent to the switches 22-29, which preferably are electronic switches. The pulse-delaying devices 32- 39 may be realized in various ways. Electrical or acoustical delay lines or lumped constant delay networks, for instance, may be used.

Insofar as the necessary delay-times are related to the velocity V of the movable electrode 10, that velocity should during printing be practically constant in order to maintain a uniform angle of inclination a. This angle a, however, may be made independent of the velocity V by substituting shift registers 42-49 as shown in FIG. 4 for the pulse-delaying devices 1 9 shown in FIG. 1. The number of sections varies from eight for the shift register 49 connected between the first horizontal row of the character generator matrix 12 and the electrode 9 to a single one in the shift register 42 adapted to provide a delay for the pulses applied to electrode 2. The electrode 1 is directly connected with the character generator matrix 12. The pulses supplied to electrode 1, therefore, are not delayed. The speed of operation of the shift registers 42-49 is controlled by clock-pulses 14, which are derived from the movement of the movable electrode 10 in such a way that eight clock-pulses are generated upon movement of the electrode 10 over the distance a=htgot. Clock-pulses such as these may be obtained by providing the driving means for moving the movable electrode with pulse generating means such as a magnetically or optically coded disc. These clock-pulses ensure that the printing control pulses supplied by the character generator matrix 12 to the electrode 9 are delayed by 8 clock pulses. In general the printing control pulses to electrode number k are delayed by k1 clockpulses. As it is intended that when the shift registers are connected in circuit all the printing control pulses supplied to any particular one of the fixed electrodes 1 9 should be delayed by the same amount, it is necessary that every possible print-control pulse supplied by the character generator matrix 12 should coincide with a clock-pulse. In the timing diagram shown in FIG. 5 successive possible print-control pulses are indicated by 51-57, the clock-pulses by 61-68. If r is the interval between successive print control pulses and s, that between successive clock-pulses, then r=ns, wherein n is an integer. Accordingly we find for the distance a: 04:88: 8r/ n and for the angle of inclination a: tgw=1/n. For a we find accordingly the following possible values:

Angle of inclination a 45 27 18 14 11 9 It may not always be possible-and it is not necessary--that the longitudinal direction of the movable electrode 10 is exactly perpendicular (or nearly so) to that of the fixed electrodes 1 9. Such is for instance the case when the movable electrode follows a helical line rotatable around its axis. In that case the invention may be utilized to on the one hand correct for the inclination of the movable electrode, so as to obtain normal perpendicular printed characters and on the other hand to obtain italicised characters having a different slant than the longitudinal direction of the movable electrode.

Suppose that the movable electrode encloses an angle 5 (FIG. 6) with the vertical and the value of f3 corresponds with one of the values for a in the above table. For the printing of normal perpendicular or italicized characters the pulses supplied to the fixed electrode 1 should be delayed by the time-interval necessary for the crossing of the movable electrode with electrode 1 to travel over the distances a =htgp3 or oq=lz(tgfitg 15) respectively. This may be obtained by an arrangement in many respects similar to that shown in FIG. 4, wherein now, however, the shift register supplying printing pulses to electrode 1 comprises 8 sections etc. The clock-pulses may be obtained in the manner illustrated with FIG. 7; a rotatable magnetic code disc 15 comprising two circular magnetic pulse-tracks 16 and 17, is mechanically coupled with the means (not shown) for moving the movable electrode 10 so as to rotate with a speed proportional to the speed of said electrode 10. The pulse-density of the tracks 16 and 17 is chosen such, that upon movement of the electrode 10 over the distance a the track 16 induces eight pulses in the associated reading head 18 and upon movement of the electrode 10 over the distance a the track 17 induces eight pulses in the reading head 19 associated with this track 17. Whether normal perpendicular characters or italics are printed is then governed by the position of the switch 20.

What is claimed is:

1. Electronically controlled character printing apparatus comprising a plurality of juxtapositioned pulse operable recording members arranged in a given pattern, a printing surface movable relative to said recording members, a character generator matrix for simultaneously generating a set of pulses containing character forming information, connecting means for applying the pulses from said matrix to each said recording member thereby to stimulate each said recording member to print a portion of a character on said recording surface and pulse delaying means within substantially all said connecting means and interposed between said character generator matrix and said recording members for delaying by different amounts each of the set of simultaneously generated pulses applied to said recording members thereby to alter, in proportion to the delay, the angular relation between adjacent components of a particular character printing by said apparatus.

2. Printing apparatus as claimed in claim 1 including switch means for selectively bypassing at least a portion of said pulse delaying means to reduce the delay produced thereby.

3. Printing apparatus as claimed in claim 2 wherein said pulse delaying means consists of shift registers, each having a different number of sections thereby to introduce different delays in different portions of a character, means for generating clock pulses, and means for coupling said clock pulse generating means to said shift registers, thereby to trigger said shift registers.

4. Printing apparatus as claimed in claim 3 wherein said clock pulse generating means includes means for sensing the relative motion between said printing surface and said recording members, and a variable frequency clock pulse oscillator responsive to said sensing means thereby to produce clock pulses having a frequency varying as a function of said motion.

5. Printing apparatus as claimed in claim 4 wherein the recording members consist of at least one fixed elongated element on one side of the printing surface and one movable element on the other side of the printing surface, said movable element traveling in a path approximately parallel with the longitudinal dimension of said fixed element, and including means for coupling said clock pulse generating means to said movable element to control the output frequency of said clock pulse generating means.

6. Electronically controlled character printing apparatus comprising a printing surface, a plurality of aligned juxtapositioned pulse operable recording members, each consisting of a fixed elongated element on one side of the printing surface, a character generator matrix for simultaneously generating a set of pulses containing character forming information, connecting means for applying the pulses from said matrix to said recording members thereby to selectively stimulate each said recording member to print a portion of a character on said recording surface, a plurality of shift registers within substantially all said connecting means and interposed between said matrix and said recording members, each said shift register having a different number of stages for delaying, by different amounts, each of the set of simultaneously generated pulses applied to said recording members thereby to alter, in proportion to the delay, the angular relations between adjacent components of a particular character printed by said apparatus, a coded magnetic disc coupled to the movable element of said recording members and having recording heads for producing clock pulses at a frequency varying as a function of the velocity of said movable element, means for coupling the clock pulses from said generating means to said shift registers thereby to control the amount of delay each said shift register produces, and switch means for selectively bypassing said shift registers thereby to selectively reduce the delay produced thereby.

7. In a matrix printer, the combination comprising: a set of M printer elements, each for printing a different portion of a character;

a separate actuating means for each of said printer elements;

character print signal producing means having M output lines, one for each said actuating means;

a first set of coupling means for coupling each of the output print signals on said M lines to the respective actuating means with substantially the same time delay;

a second set of coupling means for coupling each of said output print signals to the respective actuating means, each different coupling means of said second set providing a different time delay; and

means for applying said output print signals to either one of said first set of coupling means and said second set of coupling means selectively.

8. The combination as claimed in claim 7, wherein the progressively diifering delays provided by the different ones of said second set of means diifer from one another according to an arithmetic progression.

9. The combination as claimed in claim 7, wherein the last-mentioned means is a set of switches, and wherein in one position of the switches the output print signals are applied to said first set of coupling means, and wherein in another position of the switches the output print signals are applied to the said second set of coupling means.

10. The combination as claimed in claim 7, wherein a character is normally formed on a document by printing marks at selected ones of M rows in N successively printed columns, said M printer elements being arranged side-by-side on one side of a document printing zone at locations to print the M rows of marks, respectively; an anvil disposed opposite said printer elements on the other side of said zone; and means for moving one of said anvils and said set of printer elements relative to the other in a direction from one end of the printing zone to the other end.

11. The combination as claimed in claim 10, wherein said set of printer elements is a set of elongated print bars arrayed in parallel, side-by-side relation, each of said print bars extending the length of said printing zone, and wherein said anvil extends across the width of the arrayed bars and is moved at constant speed, during a printing operation, from one end of the print bars to the other end.

References Cited UNITED STATES PATENTS STANLEY M. URYNOWICZ, 1a., Primary Examiner G. M. HOFFMAN, Assistant Examiner US. Cl. X.R. 178-30 

